The circuit is set up so that if you push a full-range (10v point-to-point) sine wave though it at a frequency that's being boosted, it will clip. Otherwise there's a reasonable amount of headroom and a lot of boost. In other words, just enough range to push sounds into distortion. Works well in a feedback loop.

Constructed with a handful of (relatively large) 1206 capacitors and resistors, it's the perfect first project if you want to learn SMD soldering, and it comes with a detailed build guide from Thonk.

Here's a very brief demo of Simple EQ from the Brighton Modular Meet in 2015:

This is a fairly simple build, but if you have any issues, the best way to get help is to check the GitHub Issue List, and remember to check closed issues as well as open ones.